A conventional hydraulic rotary motor is typically manufactured in a way that vanes project from a rotor and rotate about a central axis of rotation. The motor includes housing where the vanes and the housing define a plurality of chambers. The motor typically has a single inlet for a working medium to enter the plurality of chambers and a single outlet for the working medium to exit the plurality of chambers where the torque to rotate the rotor is limited by the single pair of inlet and outlet.
The rotor in the conventional hydraulic rotary motor is designed to move in directions perpendicular to the central axis of rotation. A volume of each of the chambers in relation to an angular position of the chamber varies as the rotor moves in directions perpendicular to the central rotation axis during rotation of the rotor. In particular, the volume of a chamber is at its minimum and the pressure of the working medium in the chamber is at maximum as the chamber rotates past the inlet. The volume of the chamber increases and the pressure in the chamber decreases as the chamber approaches the outlet. Such a movable rotor induces uneven pressure loading and thus a severe side load to a shaft supporting the rotor. Additionally, the torque acting on each vane is not consistent during rotation of the rotor. Accordingly, it would be desirable to have a motor that addresses some of the issues described above.